: The overall goal of this R21 proposal is to utilize a novel screening approach to find small molecules that selectively modulate gene expression. This would allow combining the advantages of small molecule pharmaceuticals including cost, oral delivery, crossing the blood brain barrier and long shelf life with the specificity arising at the gene level by selectively targeting the transcription machinery. Molecular beacon detection of equilibrium cyclization uses high sensitivity fluorescence to monitor DNA-protein complex formation. The system consisting of TBP (TATA binding protein), Mot1 (modifier of transcription 1) and NC2 (negative cofactor 2) will be used as a test case. These proteins are involved in the expression of many genes in eukaryotes including humans. Small molecules will be screened for inhibition or enhancement of the formation of the TBP-Mot1-DNA complex relative to that of TBP-NC2-DNA as a function of DNA sequence. Selective molecules found in the screening will be tested in vivo on yeast. The research plan is to validate the methodology on this test system so that it can then be applied to find small molecules that specifically regulate gene expression in the brain. There are many neurological transcription systems that may be amenable to this approach including the c-Rel, RelA and p50 heterodimer and homodimer transcription factors as well as those of the CREB and CREM transcription factors that act in neuroprotection, memory formation and synaptic plasticity. PUBLIC HEALTH RELEVANCE: A novel screening approach will be used to find small molecules that selectively modulate gene expression to allow combining the advantages of small molecule pharmaceuticals including cost, oral delivery, crossing the blood brain barrier and long shelf life with the specificity that arises at the gene level by selectively targeting the transcription machinery.